ELECTRON SOURCE AND METHOD FOR MAKING THE SAME

摘要

The electron source of the present invention comprises an insulation substrate having a first conductive film formed thereon that defines an electrode, wherein said electrode attracts the electrons emitted by a field-emission cathode and comprises a surface region for a secondary electronic emission. The electron source also comprises a dielectric layer used for holding the cathode and comprising openings above the first conductive film. A part of these openings grows wider at the edge of the opening region located against the first conductive film. The electron source further comprises a second conductive film having a part thereof located on the opening walls except for the walls where the part grows wider. A part is located on the first conductive film in the opening, thus forming a second region of secondary electronic emission as well as a part that protrudes into the opening widening part, that is directed towards the edge of the part of the second conductive film located at the bottom of the opening, and that is separated by a vacuum gap from the films located at the bottom of the opening. The end of the protruding part thus defines a field emission electrode. In order to produce this electron source above the elements of the first conductive film on the insulation substrate, islands of a dual-layer complementary coating are formed, while a dielectric layer is applied and openings are formed down to the lower layer of the complementary coating. This coating is then etched and a second conductive film is formed using a vapour deposition method so as to form a disruption about the edges of the openings in the shade of the directed particle flow. The upper layer of the complementary coating islands is finally etched before forming the interconnections.